DARMSTADT, Germany — A European spacecraft went into orbit Tuesday around Venus on a mission to explore the mysterious atmosphere of Earth’s nearest planetary neighbor.

Mission controllers at the European Space Agency in Darmstadt cheered, clapped and embraced after they picked up the signal from the Venus Express probe, indicating it had completed the orbital maneuver.

The spacecraft disappeared behind the planet for about 10 minutes, leaving controllers without contact as it swung around the back of the planet, whose hot, dense atmosphere the mission plans to explore.

Europe’s space program also has a spacecraft orbiting Mars, while a third is on its way to land on a comet.

“We’ve put together a second planetary mission in as short a time as possible,” McCoy said. “We’ve put two satellites around two planets. It’s incredible what we’ve accomplished.”

The Venus Express signal reappeared as a bright green line on a screen in mission control after the maneuver, in which the Venus Express fired its main engine for 51 minutes, slowing it down so the planet’s gravity could pull it into orbit.

Officials say they could have a first picture of Venus’ south pole as early as Thursday.

Earth's very different neighbor
The space agency will use the spacecraft’s seven instruments to search for clues about why Venus wound up with an atmosphere almost 90 times denser than Earth’s and shrouded in clouds of sulfuric acid.

Of key importance will be studying Venus’ strong greenhouse effect — the way carbon dioxide traps the sun’s heat — and the permanent hurricane force winds that constantly circle it high in the atmosphere.

The instruments on board the $260 million craft include spectrometers to measure temperature and analyze the atmosphere and a special camera that will concentrate on documenting whether Venus’ many volcanoes are active.

Venus is the nearest planet to Earth within the solar system, and the two have similar mass and density. Both have inner cores of rock and are believed to have been formed at roughly the same time.

Yet despite those similarities, the two have vastly different atmospheres, with Venus’ composed almost entirely of carbon dioxide and very little water vapor. Thanks to runaway warming from its greenhouse effect, Venus has the hottest surface of all the planets, about 864 degrees Fahrenheit.

If everything goes according to plan, the European agency plans to keep the probe active for 500 days, with the possibility of extending its life by another 500 days.

The probe, coated with a metallic polymer skin to protect it from heat, is a sister craft to ESA’s Mars Express, which was launched in June 2003 and reached Martian orbit in December of that year.

The last mission to Venus was NASA’S Magellan probe, launched in 1989. It completed more than 15,000 orbits between 1990 and 1994, and mapped almost all of Venus, revealing towering volcanoes, gigantic rifts and sharp-edged craters.